what is the precipitation?
<p> recently we need test one compound in plastic materials by LC-MS .the most challenge is that how to extract the target compound from plastic materials</p><p>in our house method it described as follow :</p><p><em><strong>1.Polycarbonate (PC) extraction method
</strong> Dissolve the 1 g sample with 20 mL DCM (5.2.3), shake well until the sample totally dissolve, if thesample cannot completely dissolve, ultrasonic at 40oC for 60 minutes.
Re-precipitated the plastic with 100 mL acetone (5.2.4) with drop-wise and constant swirling.
Stand for 30 minutes to allow precipitate plastic residue.
</em><em><strong>2.Extraction method with others material
</strong> Add 20 mL to 1 g sample and ultrasonic at 40oC for 60 minutes.
Re-precipitated the plastic with 100 mL ACN with drop-wise and constant swirling.
Stand for 30 minutes to allow precipitate plastic residue.</em></p><p><em> </em></p><p><em> </em></p><p><span style="font-size: 14pt;">Now the qustion is why used different extraction solvent for different material,and why precipitate plastic residue appeared after adding </span><span style="font-size: 14pt;">ACN </span></p>
</strong> Dissolve the 1 g sample with 20 mL DCM (5.2.3), shake well until the sample totally dissolve, if thesample cannot completely dissolve, ultrasonic at 40oC for 60 minutes.
Re-precipitated the plastic with 100 mL acetone (5.2.4) with drop-wise and constant swirling.
Stand for 30 minutes to allow precipitate plastic residue.
</em><em><strong>2.Extraction method with others material
</strong> Add 20 mL to 1 g sample and ultrasonic at 40oC for 60 minutes.
Re-precipitated the plastic with 100 mL ACN with drop-wise and constant swirling.
Stand for 30 minutes to allow precipitate plastic residue.</em></p><p><em> </em></p><p><em> </em></p><p><span style="font-size: 14pt;">Now the qustion is why used different extraction solvent for different material,and why precipitate plastic residue appeared after adding </span><span style="font-size: 14pt;">ACN </span></p>
0
Answers
-
Hi TIM,
you need different solvents because it depends on the plastic you must dissolve.
you dissolve the plastic in order to release the substances you want to analyze then you precipitate the plastic so that the molecules of the polymere can't interfere.
Tetrahydrofuran dissolve PVC and acetonitrile precipitate it for example.
I'm not sure I'm clear because my english is poor...
0 -
Well,your information is useful,thank you ! As your Said, dissolving the plastic is to release the analysis substance,but it still need proved which kind of solvent is better
0
